| 摘要 |
PROBLEM TO BE SOLVED: To perform signal canalization at high speed in switching an optical path.SOLUTION: An optical transmission system 10 comprises: a transponder 13D for transmitting an optical signal; an optical branch section 17D for separating the optical signal from the transponder 13D into two; an active system optical transmission path 21 and standby system optical transmission path 21' for transmitting the separated optical signals respectively; an optical switch 32A which selects any one of two optical signals passing through the active system optical transmission path 21 and standby system optical transmission path 21', and switches from the selected optical signal to the other optical signal when input of the selected optical signal is interrupted; a transponder 13A for receiving the optical signal selected by the optical switch 32A; and an active system variable optical attenuator 20A and standby system variable optical attenuator 20A' for adjusting optical levels of the respective optical signals so that the optical levels of the plurality of optical signals input to an optical switch 18A are approximately the same. |
